Something interesting is going on with VoodooPad, winner of O’Reilly’s Mac OS X Innovators Content. It’s the best front-end to a Wiki I’ve seen, but more than that, the implementation for talking to servers is XML-RPC based and open (overview and more documentation).
The API is simple, and you could probably use it as a front-end for other custom content-management systems, not just Wiki. But it is yet another API. I wonder if they considered building off of one of the existing weblog APIs, or the Atom project.
I’m going to give VoodooPad a try for general purpose note taking. I’ve always liked the idea of a Wiki but have never been able to successfully use one for anything meaningful.